1. Field of the Invention
The present invention relates to a heat exchanger excellent in heat dissipating efficiency, in particular a heat exchanger including a base plate and heat dissipating fins to improve heat exchange between a cooling air and the heat dissipating fins by reducing a flow rate of the cooling air flowing through the heat dissipating fins.
2. Related Art
Because of the increased heat generating amount and the heat generating density, a high efficient heat exchanger excellent in heat dissipating efficiency is desired. A heat exchanger made of aluminum extruded material with a low manufacturing cost has been used. Since the base plate and the heat dissipating fins are integrally formed in the heat exchanger made of the extruded material, the manufacturing thereof is easy. In addition, the base plate and the heat dissipating fins may be separately manufactured, and the heat dissipating fins are jointed on one surface of the base plate to form the heat exchanger.
FIG. 6 is an oblique perspective view of a conventional heat exchanger. As depicted in FIG. 6, the conventional heat exchanger 100 includes a base plate 102, to one surface of which a heat generating component is thermally connected, and a plurality of plate-shaped heat dissipating fins 103 which are thermally connected to the other surface of the base plate.
A cooling air is blown by a fan or the like along a longitudinal direction of the base plate from one end thereof as represented by the numeral reference 108 in the conventional heat exchanger 100 to dissipate the heat transferred from the heat generating component through the base plate to the plate shaped heat dissipating fins into the atmosphere. In case that a plurality of heat generating components are thermally connected to the base plate along the longitudinal direction thereof, a large amount of the cooling air is blown into the plate shaped heat dissipating fins from one end of the base plate to dissipate the heat of the plurality of heat generating components (refer to Japanese Patent Application Publication No. 7-15160).
In general, the amount of the cooling air to be supplied is determined in each of the apparatus in the heat exchanger in which the plurality of plate shaped heat dissipating fins are thermally connected to the one surface of the base plate as described above. When the length of the heat dissipating fin is long and the distance between adjacent fins of the plate shaped heat dissipating fins is small, the front portion of the heat dissipating fin in the air flowing direction is hit by a cool air while the back portion of the same heat dissipating fin in the air flowing direction is not hit by the cool air. On the other hand, when the distance between the adjacent fins of the plate shaped heat dissipating fins is set to be large, and a large amount of cooling air is blown in the fins at a high speed, expecting high cooling efficiency, the cooling air passes in the central portion between the fins, resulting in that the heat exchange between the cooling air and the fins is not effectively performed. Thus, the conventional heat exchanger has a problem in which the heat of the plurality of heat generating components arranged in depth along the air flowing direction, in particular the heat of the heat generating component arranged in the leeward side is not effectively cooled.
An object of the invention is therefore to provide a heat exchanger excellent in heat dissipating efficiency in which the heat of the plurality of the heat generating components arranged in depth along the air flowing direction can be effectively cooled.